(1) Field of the Invention
The invention relates to a packaging container for bulk material, in particular a sack or bag made of plastic film, with at least one container wall enclosing the bulk material, which wall comprises a multilayer venting region extending in longitudinal direction of the container and consisting of at least one inner and one outer layer, wherein the venting region comprises at least one inner and one outer opening, wherein the inner openings are formed as apertures in a strip-shaped surface region of an inner layer of the venting region, wherein the surface region extends over at least one predetermined portion in the direction of extent of the venting region, and wherein at least one outer opening is formed in a joining seam laterally limiting the venting region wherein the outer opening in the joining seam inside the venting region has a shielding element associated with it for the deliberate diversion of at least a partial flow of the air flow passing through the venting region.
(2) Description of Related Art
It is known that packaging containers of the above mentioned kind are used for receiving pourable or free-flowing bulk materials such as for example foodstuffs, fertilizers and the like. Such pourable filling materials are a. o. manufactured in the food industry or the chemical industry or are required for further processing in a manufacturing process. The packaging containers are a means of transport for the filling materials or bulk materials, for their intermediate storage or for offering the end product contained in it for sale.
A generic packaging container is known from the DE 10 2007 022 400 A1. The venting device described herein comprises a venting channel with two separate chambers connected with each other via an overflow opening, wherein the inner venting opening is provided on the first chamber and the outer venting opening is provided on the second chamber.
The DE 20 2006 020 303 U1 describes a packaging container with walls, which form a through-passage for an air exit in a double-layer flat air exit region. The through-passage is divided into several chambers connected with each other by at least one passage, respectively, and where the inner openings and outer openings are arranged on the chambers at a distance from each other.
Another packaging container made from a flexible plastic film is known in particular from the DE 10 2004 013 469 A1, which is used for enclosing powder-like filling materials. The packaging container comprises at least one container wall enclosing the bulk material, which comprises a multilayer venting region extending in longitudinal direction of the container and consisting of at least one inner layer and one outer layer with only one chamber. In order to ensure that venting is possible from inside the container, for example, during the filling process, the venting region is provided with at least one inner and outer opening. The inner openings are primarily formed as apertures in a strip-shaped surface region of the inner layer of the venting region, so that air can flow from inside the container into between the inner and outer layer. The surface region provided with apertures roughly extends over the entire height of the venting region. An outer opening is provided in a joining seam laterally limiting the venting region, via which the air which has entered between the layers can be dissipated to atmosphere. This ensures safe venting, but in the case of relatively finely powdered filling materials it is possible that some of the filling material gets discharged from the packaging as early as during the filling process or immediately thereafter when the packaging container is subjected to a pressing operation.